Catheter balloon with biased multiple wings

ABSTRACT

A balloon catheter for dilating a stenotic region of a patient&#39;s body lumen such as an artery or for the implantation of an expandable stent within a patient&#39;s body lumen. The balloon of the catheter has a plurality of canted wings which are inclined at an angle of about 15° to about 75°, preferably about 30° to about 60° from a line tangent to an inner tubular member extending within the interior of the balloon.

BACKGROUND OF THE INVENTION

This invention generally relates to balloon catheters, particularlyballoon catheters for deploying stents, such as after percutaneoustransluminal coronary angioplasty (PCTA) procedures.

In a typical PTCA procedure a dilatation balloon catheter is advancedover a guidewire to a desired location within the patient's coronaryanatomy where the balloon of the dilatation catheter is properlypositioned within a stenosis to be dilated. The balloon is inflated withradiopaque liquid at relatively high pressures (generally greater than 4atmospheres) to dilate the stenosed region of the diseased artery. Oneor more inflations may be needed to effectively dilate the stenosis. Thecatheter may then be withdrawn from the stenosis or advanced furtherinto the patient's coronary anatomy to dilate additional stenoses.

Very frequently the PTCA treatment modality includes the placement of astent either simultaneously during the angioplasty or after a dilatationof a stenotic arterial region has been completed to provide long termlumen patency. Balloon catheters similar to those described above fordilatation are used to deploy stents within a patient's body lumen.Typically, an expandable stent is first disposed about the exterior ofthe deflated balloon on the distal extremity of the catheter in aconstricted or otherwise unexpanded condition and then the catheter isadvanced within the patient's body lumen until the stent mounted on theexterior of the balloon is at the location in which the stent is to bedeployed, e.g. at the stenotic site of a previous dilatation. Theballoon is inflated so as to expand the constricted or otherwiseunexpanded stent against the wall defining the body lumen and then theballoon is deflated and the catheter withdrawn from the patient's bodylumen. The expanded stent remains at the lumen site in an expandedcondition when the catheter is removed.

Advances in material development for relatively non-compliant balloonsdesigned for both dilatation and stent deployment have increased thetensile strength of the balloons allowing thinner balloon walls and thuslower catheter profiles. However, to obtain the benefits of a lowercatheter profile, the wings which form when such balloons are deflatedare wrapped around the inner member which extends through the interiorof the balloon. The wrapped balloon may be covered with a protectivesheath at least for handling and storage. Frequently, for stent deliveryballoons, the stent is crimped onto a protective sheath covering whichis somewhat elastically expansive so as to provide a more uniformexpansion of the stent mounted on the sheath. The wrapped wings of theballoon are usually heat set in this condition so that the wings have amemory of the small wrapped dimensions when the balloon is deflatedafter inflation, e.g. for prepping, dilatation or stent deployment.

While some improvement in balloon profile has been obtained with theprior wrapped balloons, the procedures for forming the balloon with thedesired memory complicates the manufacturing procedure and the use ofthe balloon. What has been needed is a catheter structure whichsimplifies the wrapping and eliminates the folding of the balloon wingsand the heat setting thereof. The present invention satisfies these andother needs.

SUMMARY OF THE INVENTION

This invention is directed to a catheter having a balloon on a distalextremity of the catheter shaft which has a plurality of biased wingsand to the method of forming the biased wings on the balloon.

The inflatable balloon on the catheter of the invention generally has aplurality of canted wings, each of which have been formed so as to beinclined at an angle of about 15° to about 75°, preferably about 30° toabout 60°, with respect to a tangent line extending from the exterior ofan inner member about which the wings are wrapped. The wings are formedof the cylindrical and part of the tapered ends of the balloon thussignificantly reducing the balloon profile.

The inclined or canted wings are formed by pressing suitable shapingtools against the exterior of the balloon while the balloon is inflatedat relatively low pressures of about 5 to about 20 psi, preferably about8 to about 15 psi and, once the wings have been formed by the shapingtool, the interior of the balloon is subjected to a partial vacuum, i.e.a pressure of about 10 to about 29 inches (25.4-73.7 cm) of Hg,preferably about 20 to about 27 inches (51-68.6 cm) of Hg. in order tomaintain the balloon in the constricted deflated condition with thecanted wings of the balloon inclined and partially wrapped. The cantedwings can be more easily wrapped around an inner tubular memberextending within the balloon interior to reduce the effective profile ofthe balloon. The wrapping may be performed manually or by placing theballoon within an appropriate die and rotating either the balloon or thedie or both to wrap the wings. A variety of other methods may beemployed to wrap the balloons.

The vacuum applied within the balloon interior holds the canted wings ina wrapped position long enough so that a sheath or a stent can bemounted about the wrapped wings of the balloon. A stent may also be slidover and crimped onto the sheath for subsequent deployment. Theangularity of the wings with respect to a line tangent to the exteriorof the inner member greatly facilitates the wrapping of the wings andthe reforming thereof when the deflated balloon is pulled back into asheath or the distal end of a guiding catheter.

Details of stents suitable for use with the present invention can befound in U.S. Pat. No. 5,344,426, U.S. Pat. No. 5,423,885, U.S. Pat. No.5,441,515, U.S. Pat. No. 5,443,458, U.S. Pat. No. 5,443,500 and U.S.Pat. No. 5,514,154, all of which are assigned to the present assignee.They are incorporated herein by reference. Other stent designs may alsobe employed.

In one aspect of the invention, the catheter has an elongated shaft witha proximal end, a distal end, a port in the distal end and guidewirelumen extending through at least the distal portion of the catheter toand in fluid communication with the port in the distal end of thecatheter shaft. The balloon of the invention may be mounted on a distalextremity of the catheter shaft in a conventional fashion with a distalskirt secured by fusion bonding or a suitable adhesive to a distalextremity of the inner tubular member extending through the interior ofthe balloon and a proximal skirt of the balloon is similarly secured toa portion of the catheter shaft which may be the distal extremity of anouter tubular member which in part forms the catheter shaft.

The balloon may be made from suitable thermoplastic polymeric materialsincluding high density polyethylene, polyethylene terephthalate (PET),polyamide (e.g. nylon 11 or 12), ionomers such as Surlyn sold by DuPont,polyurethane and polyamide block co-polymers such as PEBAX.

The present invention provides an intralumenal catheter with an improvedballoon member with multiple wrapped wings which are formed so as to beinclined to predispose the wings to wrapping and subjected to aninterior vacuum to hold the wings in the constricted condition. Thecrease which forms with the wing formation extend well into the taperedends of the balloon which facilitates mounting a sheath or stent ontothe wrapped balloon. A stent may be mounted and then crimped directlyonto the wrapped balloon or onto a sheath covering the wrapped balloonfor vascular deployment. The inclined wings also facilitate the pullbackof the deflated balloon after a vascular or other procedure into thedistal tip of the guiding catheter.

Long term disposition of the balloon in the wrapped condition and/orthermal treatment of the wrapped balloon effect a set which the balloontends to stay in for the duration of storage and use.

These and other advantages of the invention will become more apparentfrom the following detailed description of the invention when taken inconjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational schematic view, partially in section, of aballoon catheter embodying features of the invention.

FIG. 2 is a transverse cross-sectional view of the catheter shown inFIG. 2 taken along the lines 2—2.

FIGS. 3 and 4 schematically illustrate the forming of multiple cantedwings on the balloon.

FIG. 5 is a perspective view in section which illustrates the balloonwith multiple canted wings.

FIG. 6 illustrates the placement of the balloon with multiple cantedwings within a die for wrapping the canted wings about an inner tubularmember.

FIG. 7 illustrates the balloon in the wrapped condition within the die.

FIG. 8 is a transverse cross-sectional view which illustrates a stentdisposed about the multiwinged balloon shown in FIGS. 1-2.

DETAILED DESCRIPTION OF THE INVENTION

Reference is made to FIGS. 1-2 which illustrate a balloon catheter 10embodying features of the invention. Catheter 10 has an elongated shaft11 with proximal and distal shaft sections 12 and 13, a multiarm adapter14 on the proximal end of the shaft and an expandable balloon 15 on thedistal shaft section spaced proximal to the distal end 16. An inflationlumen 17 extends between the proximal end of shaft 11 and a locationspaced proximal to the distal end 16 and is in fluid communication withthe interior of the balloon 15. The catheter shaft 11 is provided withan inner tubular member 18 and an outer tubular member 19 of suitablepolymeric material. A guidewire receiving lumen 20 extends through theproximal and distal shaft sections 12 and 13 to the port 21 in thedistal end 16. In the distal shaft section 13, the guidewire receivinglumen 20 is defined at least in part by the inner tubular member 18.

The balloon 15 has a distal skirt 22 which is secured by suitable meanssuch as fusion or adhesive bonding to an exterior portion of the innertubular member 18 and a proximal skirt 23 which is secured by the sameor similar means to the distal end of the outer tubular member 19. Aguidewire 24 is slidably disposed within the guidewire lumen 20.

As shown more clearly in FIG. 2, the balloon 15 has a plurality ofcanted wings 25 which are deformed so as to be inclined at a suitableangle with respect to a line 26 which is approximately tangent with theexterior surface of the inner tubular member 18.

FIGS. 3 and 4 schematically illustrate the deformation of the balloon 15so as to form the canted wings 25. As shown in FIG. 3, a partiallyinflated balloon 15 (e.g. inflated to an internal pressure of about5-15psi) is surrounded by three elongated shaping tools 27. Each of theshaping tools 27 has planar surfaces 30 and 31 and may have an elongatedwedge-like deforming element 28 as shown in the drawings. The surface 31of one shaping tool 27 is configured to press against the underside of afirst canted wing 25 and the surface 30 of the same shaping tool isconfigured to press against the top side of a second canted wing 26adjacent to the first canted wing. The shaping tools 27 are assembled sothat when they are moved radially inwardly the wedge-like deformingelements 28 thereof are off-set from the longitudinal axis 32 as shownto deform the canted wing 25 in the desired manner.

While the balloon 15 is inflated at low pressures, the shaping tools 27are moved inwardly until the surfaces 30 of the shaping tools arepressed against the bottom side of the canted wings 25 and the surfaces31 of the adjacent shaping tools are pressed against the top side of thewings as shown in FIG. 4. A space of about 0.004 to about 0.008 inch ismaintained between the surfaces 30 and 31 but these surfaces do pressagainst the balloon material between these surfaces to form the wings.There is little or no deformation of the outer tip of the wings, i.e.there is no folding as was done in the prior art. The interior of theballoon 15 is then subjected to a partial vacuum which holds the cantedwings 25 in a partially wrapped condition as shown in FIGS. 2 and 5.

The canted wings 25 of balloon 15 may be wrapped about the inner tubularmember 18 by placing the distal extremity of the catheter 10 within adie 33 so that the canted wings 25 of the balloon 15 are disposed withinthe chambers 34 of the die as shown in FIG. 6. Relative rotationalmotion is effected between the die 33 and the distal extremity of thecatheter 10 so that the canted wings 25 disposed within the chambers 34are wrapped about the inner tubular member 18 as shown in FIG. 7. Whenwrapped, the tips of the wings may extend over an adjacent wrapped wingdepending upon the lengths of the wings and the diameter of the innertubular member 18 about which the wings are wrapped. Once wrapped, thecanted wings 25 have little tendency to unwrap particularly whensubjected to an internal vacuum, so a stent 54 may be readily slid overand crimped over the wrapped balloon 15 as shown in FIG. 8. Typically,when the stent 54 is disposed about the balloon 15, it is crimped ontothe exterior of the balloon 15 to facilitate the introduction of thecatheter into a patient's vascular system, but a protective sheath 53may be applied to the exterior of the balloon and the stent 54 crimpedonto the sheath.

When the balloon 15 is in the desired location within the patient'svascular system, inflation fluid is introduced into the interior of theballoon through the inflation lumen 17 to inflate the balloon and expandthe stent 54 crimped onto the balloon. Because of the multiple cantedwings 25 on the balloon 15, when the balloon inflates, it readily anduniformly expands the stent 54 mounted onto the balloon. Once expanded,the stent 54 is secured within the body lumen and the balloon may thenbe deflated and withdrawn.

While the balloon catheter with canted wings has been described hereinas a stent delivery catheter, those skilled in the art will recognizethat the catheter may be employed as a balloon angioplasty catheter todilate stenosis within a patient's coronary artery or other body lumen.When employed as a balloon angioplasty catheter, a sheath may beprovided about the balloon with canted wings to hold the canted wings inplace. Other modifications and improvements may be made to the inventionwithout departing from the scope thereof.

What is claimed is:
 1. A balloon catheter, comprising: a) an elongatedshaft having proximal and distal ends, a port in the distal end, aninner tubular member defining at least in part a guidewire lumenextending to and in fluid communication with the port in the distal endand an inflation lumen extending to a location spaced proximal to thedistal end; and b) an inflatable deflated balloon on a distal portion ofthe elongated shaft and having an interior in fluid communication withthe inflation lumen and having a first unwrapped configuration and asecond wrapped configuration when the balloon is wrapped around theinner tubular member, the balloon in the first unwrapped configurationhaving a plurality of canted wings, each of which is formed to have abase inclined at an angle of about 15° to about 75° from a line at thebase of said wing tangent to an exterior surface of the inner member,the angle being measured in a cross-sectional plane which isperpendicular to the longitudinal axis of said elongated shaft, and theballoon in the second wrapped configuration having a curvilinearjunction between the base of the wing and a balloon section locatedbetween the wing and an adjacent wing.
 2. The catheter of claim 1wherein the balloon has at least three canted wings.
 3. The catheter ofclaim 1 wherein the balloon is formed of a thermoplastic polymericmaterial.
 4. The catheter of claim 3 wherein the thermoplastic polymericmaterial is selected from the group consisting of polyolefins,polyesters, polyamide, polyurethanes and copolymers and blends thereof.5. The catheter of claim 1 wherein the interior of the balloon is at apartial vacuum of about 10 to about 29 inches of Hg.
 6. The catheter ofclaim 1 wherein the interior of the balloon is at a partial vacuum ofabout 20 to about 27 inches of Hg.
 7. The catheter of claim 1 whereinthe base of each wing of the balloon is inclined at an angle of about30° to about 60° from the line at the base of said wing.
 8. A method offorming a low profile balloon formed of relatively non-compliantpolymeric material having a plurality of wings canted at an anglecomprising: a) providing a balloon having a cylindrical working sectionand tapered ends which define an interior chamber within the balloon andan elongated tubular inner member extending within the interior chamberof the balloon; b) inflating the balloon to a pressure of less than 20psi; c) pressing a plurality of shaping surfaces against the exterior ofthe inflated balloon so as to form a plurality of wings, each winghaving a base inclined at an angle of about 15° to about 75° from a lineat the base of said wing tangent to an exterior surface of the innermember; d) subjecting the interior chamber of the balloon to a partialvacuum of about 10 to about 29 inches of Hg; and e) wrapping the wingsabout an inner member.
 9. The method of claim 8 wherein at least threeshaping members are pressed against the exterior of the partiallyinflated balloon.
 10. The method of claim 8 wherein the vacuum appliedwithin the interior of the balloon is about 20 to about 27 inches of Hg.11. A method of mounting a cylindrically shaped stent onto cylindricallyshaped balloon on a stent delivery catheter, comprising: a) providing astent delivery catheter having proximal and distal portions and aballoon on the distal portion having a cylindrical working section andtapered ends which define an interior chamber within the balloon and anelongated inner member extending within the interior chamber of theballoon; b) inflating the balloon to a relatively low pressure; c)pressing a plurality of shaping surfaces against the exterior of thepartially inflated balloon so as to form a plurality of wings each winghaving a base inclined at an angle of about 15° to about 75° from a lineat the base of said wing tangent to an exterior surface of the innermember; and d) reducing the pressure within the interior chamber of theballoon to a vacuum of about 10 to about 29 inches of Hg so as tomaintain the balloon wings in the desired inclined position; e) wrappingthe wings about the balloon in the same directions as the wings areinclined; f) mounting a stent about the wrapped balloon; and g) crimpingthe stent onto the wrapped balloon.
 12. The method of claim 11 wherein avacuum of about 20 to about 27 inches of Hg is applied to the interiorof the balloon.
 13. A stent delivery system, comprising: a) a catheterwith an elongated shaft having proximal and distal ends, a port in thedistal end, an inner tubular member defining at least in part aguidewire lumen extending to and in fluid communication with the port inthe distal end and an inflation lumen extending to a location spacedproximal to the distal end, and an inflatable deflated balloon on adistal portion of the elongated shaft and having an interior in fluidcommunication with the inflation lumen and having a first unwrappedconfiguration and a second wrapped configuration when the balloon iswrapped around the inner tubular member, the balloon in the firstunwrapped configuration having a plurality of canted wings, each ofwhich is formed to have a base inclined at an angle of about 15° toabout 75° from a line at the base of said wing tangent to an exteriorsurface of the inner member, the angle being measured in across-sectional plane which is perpendicular to the longitudinal axis ofsaid elongated shaft, and the balloon in the second wrappedconfiguration having a curvilinear junction between the base of the wingand a balloon section located between the wing and an adjacent wing; andb) an expandable stent mounted on the exterior of the balloon.
 14. Thestent delivery system of claim 13 wherein a sheath is disposed betweenthe exterior of the balloon and the stent mounted thereon.
 15. A ballooncatheter comprising: a) an elongated shaft having proximal and distalends, a port in the distal end, an inner tubular member defining atleast in part a guidewire lumen extending to and in fluid communicationwith the port in the distal end and an inflation lumen extending to alocation spaced proximal to the distal end; and b) an inflatabledeflated balloon on a distal portion of the elongated shaft which has aninterior in fluid communication with the inflation lumen and which has aplurality of canted wings, each of which is formed to have a baseinclined at an angle of about 15° to about 75° from a line at the baseof said wing tangent to an exterior surface of the inner member, theangle being measured in a cross-sectional plane which is perpendicularto the longitudinal axis of said elongated shaft, and wherein each ofthe wings is substantially straight as viewed in a cross-section takenperpendicular to the longitudinal axis of said elongated shaft.
 16. Astent delivery system comprising: a) a catheter with an elongated shafthaving proximal and distal ends, a port in the distal end, an innertubular member defining at least in part a guidewire lumen extending toand in fluid communication with the port in the distal end and aninflation lumen extending to a location spaced proximal to the distalend, and an inflatable deflated balloon on a distal portion of theelongated shaft which has an interior in fluid communication with theinflation lumen and which has a plurality of canted wings, each of whichis formed to have a base inclined at an angle of about 15° to about 75°from a line at the base of said wing tangent to an exterior surface ofthe inner member, the angle being measured in a cross-sectional planewhich is perpendicular to the longitudinal axis of said elongated shaft,and wherein each of the wings is substantially straight as viewed in across-section taken perpendicular to the longitudinal axis of saidelongated shaft; and b) an expandable stent mounted on the exterior ofthe balloon.
 17. A balloon catheter, comprising: a) an elongated shafthaving proximal and distal ends, a port in the distal end, an innertubular member defining at least in part a guidewire lumen extending toand in fluid communication with the port in the distal end and aninflation lumen extending to a location spaced proximal to the distalend; and b) an inflatable deflated balloon on a distal portion of theelongated shaft and having an interior in fluid communication with theinflation lumen and having a first unwrapped configuration and a secondwrapped configuration when the balloon is wrapped around the innertubular member, the balloon in the first unwrapped configuration havinga plurality of canted wings, each of which is formed to have a baseinclined at an angle of about 15° to about 75° from a line at the baseof said wing tangent to an exterior surface of the inner member, theangle being measured in a cross-sectional plane which is perpendicularto the longitudinal axis of said elongated shaft.